RU2660970C1 - Method of manufacture of light composite aggregate for concrete - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to the construction and industry of building materials, in particular to methods for manufacturing lightweight composite aggregates for concrete. Method of manufacturing a light composite aggregates for concrete includes the manufacture of core aggregate by softening waste paper in 10 % solution of liquid glass, drying of the core for one hour at 110 °C, formation of a shell on the surface of the core by rolling it in a granulator in a mixture obtained by the joint milling of tripoli powder, Portland cement and high-strength separated gypsum, when moistened with 20 % aqueous solution of liquid glass, drying of the prepared aggregate at a temperature of 40 °C.

EFFECT: decrease in bulk density and thermal conductivity with sufficient strength of the aggregate.

1 cl, 3 tbl, 1 ex

Description

The invention relates to the construction and construction materials industry, in particular to methods for manufacturing lightweight composite aggregates for concrete, to reduce density, lower thermal conductivity of building products and structures.

A known method of manufacturing a lightweight non-fired ash gravel, including preparing the core by wetting it with liquid glass, forming a shell on it using water-moistened ash and Portland cement during rolling in a granulator and heat treatment by steaming the raw material obtained, use expanded polystyrene 2-12 mm in size as the core, as ash - high-calcium fly ash obtained from the burning of Irsha-Borodino coal with a specific surface area of 350-400 m ² / kg, the formation of the shell is carried out in two stages, moreover, 80% of the ash and 73% of the water quantity are fed to the granulator in the first stage, and after 3-4 minutes of granulation in the second stage, an ash-cement mixture containing the remaining 20% ash and water - the remaining 23%, in the following ratio components, wt.%: the specified fly ash 63.28-66.92, Portland cement 5.35-7.59, expanded polystyrene 0.58-0.60, water glass 7.2-8.7, the rest is water (patent RU No. 2490225, IPC С04В18 / 08, published on 08.20.2013).

The disadvantages of this method include the high bulk density and technological difficulties of working with polystyrene.

There is also known a method of manufacturing non-calcined porous gravel, comprising two-stage granulation of raw materials and including obtaining a core and shell of gravel, manufacturing a core of granules, wetting the core with sodium liquid glass, creating a shell of granules, hardening in natural conditions. The raw materials for obtaining the gravel core are paper waste and a 12% solution of sodium liquid glass, for the production of shell - Portland cement M400D20 (CEM II / A-Sh 32.5 N), building gypsum (G-6, G-7), Ash Beloberezhskaya CHP. The granules obtained had a bulk density of 423 kg / m ³ , a compressive strength of 2.4 MPa, a thermal conductivity of 0.13 W / m⋅ ° C, and water absorption by weight of 30.4%. [Lasman I.A. Unbaked porous gravel for lightweight concrete: Dis. Cand. tech. sciences. - Moscow: MGSU, BGITA, 2000. - 161 p.]

The disadvantage of this method is the high bulk density, thermal conductivity, as well as increased water absorption.

The technical problem underlying the claimed invention is to implement a method of manufacturing a lightweight composite aggregate (LKZ) for concrete, which allows to reduce bulk density and thermal conductivity, with sufficient strength of the aggregate.

The problem is solved in that a method of manufacturing a lightweight composite aggregate for concrete, including preparing a paper core by wetting it with liquid glass, forming on its surface, when rolling in a granulator, a shell using a gypsum-cement-pozzolanic binder, consisting of Portland cement, gypsum and pozzolanic additive , characterized in that when forming a shell on the surface of the core by rolling it in a mixture obtained by joint grinding of yarn, Portland cement and high-strength gypsum CA, they are moistened with a 20% aqueous solution of liquid glass, and in the manufacture of the core of filler paper waste paper is softened in a 10% solution of liquid glass, then the cores are dried for one hour at a temperature of 110 ° C, and the finished filler is dried temperature 40 ° С.

The liquid glass solution used as a technological bond increases strength and lowers water absorption without a significant increase in density.

Thanks to the manufacture of the paper core, the weight of the material is reduced, a layered structure is created, as a result of which its thermal conductivity is reduced. The presence of a durable shell allows the material to withstand the stresses that arise during the production process.

Using the drying of granules, you can get the optimal ratio of strength and bulk density of the aggregate.

Example.

As initial components for LKZ were used:

- tripoli (LLC Glavbudkom, Ukraine, Kirovograd region, Kirovograd)

- Portland cement CEM I 42.5N GOST 31108-2003 (Belarusian Cement Plant OJSC, Republic of Belarus, Mogilev region, Kostyukovichi)

- high-strength separated gypsum G-10 (LLC Unistrom-Trading, Moscow)

- liquid sodium glass Universal (LLC NPO Silikat, St. Petersburg)

- paper waste

- water

Characteristics of raw materials are presented in table 1.

Obtaining LKZ involves granulation of raw materials and includes the following technological processes: preparation of raw materials to obtain a core and a shell of granules; manufacture of core aggregates; creating a shell from a raw mix of gypsum-cement-pozzolanic binder; drying.

An example of preparing a light composite aggregate:

To prepare 1 m ^{3 of} aggregate, 115.92 kg of paper waste paper was cut, softened in 464 l of a 10% liquid glass solution, the raw material was granulated to a diameter of 10-12 mm in a laboratory plate granulator, followed by drying at a temperature of 110 ° C. To prepare the shell, we used a mixture obtained by co-grinding 32.2 kg of yogurt, 32.2 kg of Portland cement, 96.6 kg of high-strength gypsum. Next, granulation was performed by pelletizing the core of the granules in a shell mixture. Humidification was carried out with a 20% aqueous solution of water glass in an amount of 65 l. We obtained the most optimal modes of granulation of raw materials in a dish-shaped granulator: pelletizing time of 5 minutes, rotation speed of 10 rpm, granulator tilt angle of 55 °. Next, the granules were dried.

Examples of compositions and test results of the LKZ and prototype are shown in tables 2 and 3, respectively. The technical result was evaluated in accordance with the methods of GOST 5758 “Inorganic porous aggregates for construction work. Test Methods. "

The table shows that for the first composition, the bulk density is 73 kg / m ³ (17%) lower than that of the prototype, LKZ 1 water absorption is 2.4% lower than that of the prototype, while the strength index is 2.1 MPa, which lower than the strength of the prototype, but enough to withstand the necessary technological operations.

The proposed method for producing composite lightweight aggregate allows you to get aggregate for concrete with reduced bulk density and thermal conductivity, as well as with sufficient strength.

Claims (1)

A method of manufacturing a lightweight composite aggregate for concrete, including preparing a paper core by wetting it with liquid glass, forming a shell on its surface when rolling in a granulator using a gypsum-cement-pozzolanic binder consisting of Portland cement, gypsum and pozzolanic additive, characterized in that when forming the shell on the surface of the core by rolling it in a mixture obtained by joint grinding of yarn, Portland cement and high-strength gypsum, moisturize with 20% aq m solution of liquid glass, the core filler in the manufacture of paper waste paper is softened in a 10% solution of waterglass, and then dried in a nucleus for one hour at a temperature of 110 ° C, and the finished filler undergoes drying at a temperature of 40 ° C.